Air cooled internal-combustion engine



Jan. 18, 1955 E. c. KIEKHAEFER 2,699,764

AIR coousn INTERNAL-COMBUSTION ENGINE Filed Feb. 14, 1952 2 snets-sheet1 lill/111111111111111 INV l I fr @jf-ahy@ Jan. 18, 1955 E. c.KIEKHAEFER AIR cooLED INTERNAL-COMBUSTION ENGINE 2 SheetS-Sheeb 2 FiledFeb. 14, 1 .952

United States Pate-nt-Oiice 2,699,764 `azextted Jan. 18,v 1955LIlfCooLED mrERNL-COMBUS'TIN Elsa C Kia-haces Cedars-fe 1Wi ,s i@Applicaties Februar-y 14, 1952, 's4eria1 run-271,506

, .s claims.. (on. 12s-141.6)

invention relates .to p .internal-combustionengines .andparticularly.to.air-.coolingzsystems therefor. a A.

.charging. as the cylinder is exhausted.-l L.. The .spark plug -12 ofeach cylinder 4 and 5. is-energizedby .the magneto. unit 13` whichissupported by .thecircular liange .14 at the forward end-oi the engine.Thetwocycle.operation of the engine allows the-magneto .1o. be directly.mounted on the crankshaft 3 for operation.

vairfreinet-heA correspondinglcranklchamber 8 through the passage 11into the cylinder for scavenging-and; r'e- The rotor 1S and cam 16 ofthe magneto areffixedon `the .shaft 17 .or..overhanging end VjournalYof` crankshaft .3 which is supported in the bearing 18 adjacent-'tothe.rotor and-cam. The-stators 19 are mounted onthe-plate I .1`he,invention` providesan impeller of. centrifugal operationhaving a'nurnberofaxial dischargeswhereby `the 'air.may .be more easily directedas.requ1red.to.the`yliriders of/the engine,. and Aparticularlythe.moreremote of. two or more .cylinders arranged in-.lineand both .sidesthereof...A An object. of the. invention is.to provide for.v delivery`Aof equal .amounts of..air toeach .ofthe .cylinderso an infline engineat all. speeds, .particularly lat idlingas wellas at high speed .and to.both sides-of .the enginein the required amounts..

A .further .object is toA .reduce .-.snbstantially .the vanes and ductsnormally required; to leect equalcooling of `the several. cylinders..

AnotherY object is toprovide'icontrol of .the-axiaLair discharge of theirnpeller..tovreach4 the remotelcylinders of the engine. Anotherobjectis to provide-forthe easieranaintenance 4v01? the. impeller .and .easieraccess to .theimpeller blades -andxthe casing.

.A further object is 4tohprmoyicle an:irripell-er..casing`isselfcleaning and more .readily suited..fo r. usefin .chain .saWenginesandthe like.. ,g

.Anotherobject is to mount the im'peller` on-the engine.shaftandxoventhe magneto Aand provide` .forl delivery lof air to theengine cylindersfor coolingy withsubstantial These .and otherobjects.andadvantageswillbe Amore fully set. forth. in thefollowingdescription of sa. preferred embodiment of .the inventionas..illustrated:.in theiacom -panying drawing.` L.In ,the drawing:.

Fig 1 is a top. plan `v'ew.ofithe.engineA with-.parts .thereof brokenaway and sectionedzto. showthe 'magneto andfdetails of construction.of.the.impellerlcasing-and scroll;

Fig. .2 ishaside elevation.ofdthe-.enginewith theA ini- --pleller casingremovedand. with` .the scroll .broken away and sectioned to show thescroll congurationlin relation Eig. 3 is .atransverse .section through.the-.engine look- Aing toward thefscroll ,member andwith .tially brokenaway andsectionedpandtjf thelatter par Fig, 4"is a front elevationof.the..engineandi-impeller casing with apart `of .thelatter-broken.`away''toA show the impellerandscroll member.

1 The engine 1 shownin the vdrawings the.

`ca`se 2whichcarries the. horizontalcrankshaft The Otwo.Cylinders 4 and5 are arranged infline andextend `horizontallyon onesideof the;engine.

by the piston' to allow. transfer of` the compressed fuel .timing .oftheignition -the .reciprocation lof the-pistons.

Led on. .shaft 17 of the crankshaft .number to allow arelatively-freeair A20. which. latterl carries the-timing -meansf 21- operated ...by..the cam 16p. Plate 20 `is--mounted on Harige-14 -for rotationaladjustment on the crankshaft axis wherebythe may be adjustedinrelation-.t0

The external'danges 22 of cylinders `land 5' provide ..the..heatdissipation necessary for cooling of the-,cylinders 20} `.The vflanges`are-formed integrally with the outer-cast by. passingair over thecylinders and between the-flanges.

portion of cylinders '4 and-5 andextend radiallythereof.

.The anges. are arranged in a series extending the-length ofthecylinders. over passages 11 `formed therein `and .surroundports-Sthereof.

The .air is supplied by the-impeller 23 whichismount- 3 to rot-atetherewith.

lnipelleixt?) includes `thebushing -24 .which-is-mounted -directly onthe tapered portion 25- of Vshaft 17' and extends` over .the reduced andthreaded. end-260i -the shaft;

AThe hubportion 2.7 of the impeller mounted on bushing .24. andthe .skirt A2S .are annularly formedl andi-extend .oyen-.the magnetol.y.peller are formed integrally with hub 27-and`skirt`-28 .and extend tothe edge ofthe skirt. VThe forward-inner .ends of `the vanes' 'areradially spaced-from the. a-xis lof The-radial vanesV 29 oftheimj-rotation. of the impeller.H The `nut 30 which is turnedwinlone'direction on the threaded-end 26 of shaft- -17- securesthenimpeller on bushing 24- and the bushing on Vthe -tapered portion- 25 of shaft 17.

If. desired, nutl30=may be-iitted within bushing-24 to engage andwithdrawthe s'arne `for-removal ofthe irnpellerA from. the. shaft byturning nut-Silin the lopposite direction.

, According `to Vthe. inventiong-the outer edge of each vane isgenerallyarcuate -to fit within the hemispherical casing 31 .supportedby thescroll plate: 32;- Plate 32 --comprises preferably asingle-cast-memberforminga part .of crankcase.

2 and-supporting the bearingl-jfor shaft 17. The outerrdimension ofplate 32 is generally circular and includes a projecting- Wall 33which-extends alongside and .to the end 'of the thereto; The annularange34 .forwardly of. theengine and is provided with a"- marginal -recess354 in the .front outer edge circumferential. offset margin 36-cylinder- A, adjacent of plate 32 `projects -thereoi to -rec'eive .theVor" casing 3-1 with ja tight t and to support-the casing. The several#spaced .lugs.3.'7 .extending from the plate into thecasing-are drilledand tapped to receive the screws 38 for securing -the casing thereto.

Casing 31 as provided is, readily removable by removingrscrews 38 andhasa-spherical interior surfacewhich isyunobstructed for `wiping clean atfrequent-intervals 'as required. in .certaintypes of service -and-foroperation of the impeller with maximum eiiiciency and' a minimumpressure loss due to friction. p

The hernispherical-casing .31 is readily "adaptedto be ``variouslyformed, e.. g. stamped,- spun,V or die-cast. 1 The :cas1ng31Lshown1n thedrawings-is spun-as a bowl w1th the offset margint36 whichiitsthe-marginal recess35f-of plate 32. asA described. The central air:inlet-of*` the-casing comprises a plurality of-holes 39-Which are-oasizeand intake: While excluding foreign matter such as wood chips,leaves and thelike. If desired a screen of any suitable meshV mayalso.be 4mounted over the air; inlet 0r substituted 'for the series of ..1The .interior-spherical dimension "oficasing L31 islarger.thantheoutlines of vanas-29 allowingthroughout-amini- `mum .clearancetherebetween suiicient -for relative -free movement. The. casing .is.dismounted from--plate--S-ZI-by removing screws 38 which with removalof the casing allows access to impeller 23 and the interior and outlets40 and 41 of plate 32. The removal of impeller 23 thereafter providesunrestricted access to and from all sides of magneto unit 13.

-low the air to pass therethrough in a direction beneath `cylinders 4and 5 and between cover 43 and the cylinders.

Y According to the invention the air is driven by centrifugal forceaxially into the scroll 45 formed in plate 32 and continues to moverotationally therein until reaching openings 40 or 41. Scroll 45 is ofaxial development and extends in a circle about the axis of rotation ofthe impeller and terminates at opening 40. A part of the air deliveredby impeller 23 passes through opening 40 from scroll 45 or is deflectedthrough opening 40 by the cut-off member 46 formed integrally with plate32. Member 46 is angularly disposed and extends from opening 40 alongthe back side of wall 33 and adjacent to cylinder 4. The air passingthrough opening 40 into hood 42 blankets cylinders 4 and 5 with coolingair which passes over flanges 14 thereof towards the rear of the engine.The cut-off member 47 is integrally formed with plate 32 and isangularly disposed to deflect air through opening 41. Member 47 projectswithin plate 32 towards the impeller into the rotationally moving airstream and delivery of the air necessary to cool the underside of thecylinder. The air from opening 41 passes between cylinders 4 and 5 andcover 43 towards the rear of the engine or through the openings in thecover provided for pipes 44. The separate streams of air passingV overthe cylinders from openings 40 and 41 cool the corresponding parts ofthe cylinders which include4 the transfer passages 11 and exhaustopenings 9. The relative sizes and locations of openings 40 and 41 andmembers 46 and 47 provide a division of the cooling air delivered andprovide the desired relative cooling of the exhaust-and-transfer-portsides of the cylinders. The air from both sides of the cylinders vpassesfrom between hood 42 and cover 43 at the rear of the engine.

In the embodiment shown, the proportion of air cooling the transfer portside of cylinders 4 and 5 increases with the speed of the engine andtotal air-delivery of impeller 23 to coincide with the general coolingrequirements of the type of two-cycle engine shown and described.

Conditions of service such as in chain saw units, or where excessivedust and dirt are prevalent, create problems of frequent cleaning of theimpeller and casing. The ease of removal of casing 31 which providesaccess to impeller 23 and the ease of cleaning the bowl-shaped casingparticularly affords some assurance of the proper maintenance andcleaning necessary.

The impeller operates within casing 31 with a minimum of frictionallosses which allows the magneto to be advantageously mounted on thecrankshaft between the impeller and the engine without disadvantage. Theair from the impeller and casing is discharged axially into scroll 44.The scroll is developed axially to outlet 40 from which the air isreleased. Without guide vanes, the air passes over cylinders 4 and 5 insubstantially equal amounts.

The hemispherical casing is virtually self-cleaning by reason of thesmooth inner contour and the axial discharge of the casing into thescroll plate. The discharge of air from the entire perimeter of thecasing is allowed without Vobstruction with the exception only of thesmall lugs 37 which support the casing.

Various embodiments of the invention may be employed wihii the scope ofthe accompanying claims.

c aim:

l. In an internal combustion engine of the class dey having a hub andextending skirt, a series of blades extending radially from said hub andaxially along said skirt, a hemispherical casing for said impeller, saidblades having an outer dimension providing a minimum operating clearancewith the interior of said casing and providing for the axial dischargeof air from between said skirt and said casing, a scroll plate securedto and closing said casing at the periphery thereof and having adischarge opening adjacent to one of said cylinders, and a cut-offmember extending along one side of said opening to direct the air to theside of said last named cylinder immediate thereto, the scroll of saidmember extending circularly to the adjacent side of said dischargeopening and of axial development to receive the air from said casing anddischarge the air through said opening in a direction toward the otherside of said cylinder.

2. In an engine of the class described, a series of cylinders arrangedin-line and having external fins for aircooling, said cylinders havingparts with dissimilar cooling requirements on corresponding sides, animpeller mounted on the projecting forward end of the engine crankshaftto rotate therewith and having a hub and extending skirt, a series ofblades extending radially from said hub and axially along said skirtrearwardly toward said cylinders, a hemispherical casing for saidimpeller, said blades having an outer dimension providing a minimumoperating clearance with the interior of said casing and for the axialdischarge of air from between said skirt and said casing, a scroll platesecured to said engine to support said casing at the periphery thereofand having separate discharge openings adjacent to the forwardmostcylinder, and cut-off members carried by said plate at each openingthereof to direct given proportions of air to said parts of saidforwardmost cylinder, said member including a scroll of axialdevelopment to receive the air from said casing and extending to one ofsaid discharge openings to discharge the air through said opening in adirection rearwardly toward the rearwardly disposed of said cylinders.

3. In an engine of the class described, having a crankshaft and amagneto operatively mounted on said crankshaft forwardly of the engine,a series yofcylinders arranged in-line and having external tins forair-cooling, an impeller mounted on said engine crankshaft to rotatetherewith and having a hub and a skirt extending over said magneto, aseries of blades extending radially from said hub and axially along saidskirt rearwardly toward said cylinders, a hemispherical casing for saidimpeller, said blades having an outer dimension providing a minimumoperating clearance with the interior of said casing and providing forthe axial discharge of air from between said skirt and said casing,ascroll plate secured to said engine and between the latter and said'magneto to support said casing at the periphery thereof, said platehaving a dischargeopening adjacent to the forwardmost cylinder and acut-off member extending along one side of said casing at said openingto direct the air to the adjacent parts of said forwardmost cylinder,said plate having a scroll of axial development to receive the air fromsaid casing and extending to said discharge opening to discharge the airthrough said opening in a direction rearwardly toward the rearwardlydisposed of said cylinders.

4. In'an engine of the class described, a series of cylinders arrangedin-line and having external tins for aircooling, an impeller mounted atthe forward end of the engine crankshaft to rotate therewith and havinga hub and a rearwardly extending skirt, a series of blades extendingradially from said hub and axially along said skirt toward saidcylinders, a hemispherical casing for said impeller and having a centralscreened inlet opening, said blades having an outer dimension providinga minimum operating clearance with the interior of said casing anddisposed for the axial discharge of air from said casing, and a scrollmember having a discharge opening adjacent to the cylinder immediatethereto and secured to said engine, said member having an annular flangeVfitting within the periphery of said casing toV support the latter andallowing removal thereof for cleaning and access to said impeller.

5. In an engine of the class described, a series of cylinders arrangedin-line and having external fins for aircooling, an impeller mounted onthe projecting forward end of the engine crankshaft to rotate therewithand having a hub and extending skirt, a series of blades extendingradially from said hub and axially along said skirt rearwardly towardsaid cylinders, a hemispherical casing for said impeller and having acentral screened inlet opening, said blades having an outer dimensionproviding a minimum operating clearance with the interior of said easingand for the axial discharge of air from between said skirt and saidcasing, a scroll plate secured to said engine supporting said casing atthe periphery thereof and having a discharge opening adjacent to theforwardmost cylinder, and a cut-olf member extending along one side ofsaid plate at the opening thereof to direct the air to the adjacentparts of said forwardmost cylinder, said plate including a scroll ofaxial development to receive the air from said casing and extending tosaid discharge opening to discharge the air through said opening in adirection rearwardly toward the rearwardly disposed said cylinders, saidcasing being adapted to be removed from said member for cleaning andaccess to said impeller.

6. In an engine of the class described, a series of cylinders arrangedin-line and having external fins for aircooling, said cylinders havingparts with dissimilar cooling requirements on corresponding sides, animpeller mounted on the projecting forward end of the engine crankshaftto rotate therewith, a casing for said impeller, a scroll plate securedto said engine to support said casing at the periphery thereof andhaving separate discharge openings adjacent to the forwardmost cylinder,cut-of`f members carried by said plate at each opening thereof to directgiven proportions of air to said parts of said forwardmost cylinder, andcover members extending over said cylinders and enclosing said openingsto receive the air from said casing and direct the air over saidcorresponding parts of said cylinders in a direction rearwardly of saidengine.

7. In an engine of the class described, a series of cylinders arrangedin-line and having external ns for aircooling, said cylinders havingparts with dissimilar cooling requirements on corresponding sides, animpeller mounted on the projecting forward end of the engine crankshaftto rotate therewith, a casing for said impeller, a scroll plate securedto said engine to support said casing at the periphery thereof andhaving separate discharge openings adjacent to the forwardmost cylinder,cutoff members carried by said plate at each opening thereof to directgiven proportions of air to said parts of said forwardmost cylinder, andcover members extending over said cylinders and enclosing said openingsto receive the air from said casing and conduct the air over saidcorresponding parts of said cylinders rearwardly of said engine, saidplate including a scroll of axial development to receive the air axiallyfrom said casing and extending to the side of one of said dischargeopenings to discharge the air through said opening in a direction towardthe rearwardmost cylinder.

8. In an engine of the class described, a series of cylinders arrangedin-line and having external fins for air-cooling, said cylinders havingparts vwith dissimilar cooling requirements on corresponding sides, animpeller mounted on the projecting forward end of the engine crankshaftto rotate therewith, a casing for said impeller, a scroll plate securedto said engine to support said casing at the perpihery thereof andhaving separate discharge openings adjacent to the forwardmost cylinder,and cutoff members carried by said plate at each opening thereof todirect given proportions of air to said parts of said forwardmostcylinder, said member including a scroll of axial development to receivethe air from said casing and extending to one of said discharge openingsto discharge the air through said opening in a direction rearwardlytoward the rearwardly disposed of said cylinders.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,146 Packwood Sept. 13, 1949 2,233,825 Walsh et al Mar. 4, 19412,236,706 Damonte Apr. 1, 1941 2,245,989 Leathers June 17, 19412,326,335 Dehn Aug. 10, 1943 FOREIGN PATENTS 578,131 Germany June 10,1933 667,397 Germany Nov. 10, 1938 360,103 Italy June 11, 1938 505,078Great Britain May 2, 1939

